In this application several publications are referenced by Arabic numerals in brackets [ ]. Full citations for these publications may be found at the end of the written description immediately preceding the claims. The disclosures of all such publications, in their entireties, are hereby expressly incorporated by reference in this application as if fully set forth, for purposes of indicating the background of the invention and illustrating the state of the art. The basic functions of a digital binary computer are performed by devices that are capable of reversibly switching between two states often referred to as “0” and “1.” Semiconductive devices that perform these various functions must be capable of switching between two states at very high speed using minimum amounts of electrical energy in order to enable the computer to perform useful work. At the present time, integrated circuits containing millions of transistors made from elemental, compound and alloy semiconductors such as silicon (Si), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs) perform the basic switching functions in computers.
While extraordinary advances have been made in device miniaturization, fundamental physical limitations exist that prevent miniaturization beyond a certain point. Individual molecules are hundreds of times smaller than the smallest features conceivably attainable by semiconductor technology. Because it is the area taken up by each electronic element that matters, electronic devices constructed from molecules can be hundreds of times smaller than their semiconductor-based counterparts. Moreover, individual molecules are easily made exactly the same by the billions and trillions. The dramatic reduction in size, the sheer enormity of numbers in manufacture, and reversibility of switching operation are the prime benefits promised by the field of biomolecular switching using globular proteins such as cytochrome c, BSA or cytochrome c3.